This invention relates to air conditioners in general and, in particular, to a year-round air conditioner of compact design with air cooling, air heating, humidification, and filtration capabilities. Still more particularly the invention pertains to improvements in a year-round air conditioner of the type incorporating an endless band of porous material traveling in partial immersion in water to provide for air cooling and humidification.
Japanese Utility Model Laid-Open No. 151671/1977 and U.S. Pat. No. 3,476,365 represent examples of prior art air conditioners of the class in question. The Japanese utility model application proposes a device primarily for use as an air cooler. A fan-induced airstream passes the wetted endless band of porous material thereby to be cooled by virtue of the latent heat of vaporization of the water. The fan subsequently expels the thus-cooled air out into the room or like space to be conditioned.
The device according to the above cited U.S. patent, on the other hand, is intended for use as an air humidifier. The device of the U.S. patent also has a wetted endless band traveling between two separated rolls, the lower end of the band being immersed in water contained in a water tank.
If an electric heater is built into these devices with suitable controls, they function as simple year-round air conditioners. Japanese Utility Model Laid-Open No. 175920/1982, filed by the assignee of the instant application and published Nov. 6, 1982, suggests an example of such year-round air conditioners. A brief study of the device disclosed therein will manifest the problems to be solved by the present invention.
The year-round air conditioner disclosed in the just-mentioned Japanese application includes an endless band of porous material extending between and traveling around a pair of spaced rolls, one of which lies in a water receptacle on the bottom of the conditioner housing so that the porous band is constantly moistened. A fan draws ambient air into the housing through an air inlet in its back wall. The incoming air passes the moist traveling band and is expelled through an air outlet in the front wall of the housing. Disposed between the porous band and the fan is an electric heater with a guard screen for the protection of the band from the heater. The heater is, of course, set in operation for the production of warm air and out of operation for the production of cool air.
An objection to this known year-round air conditioner is the arrangement of the heater, together with the guard screen, between the porous band and the fan. During cooling, the heater with the guard screen serves no useful purpose but only obstructs the flow of cool air from the porous band toward the air outlet, thus giving rise to noise.
Another problem of this device arises by reason of the limited capacity of the electric heater, limited because it is fed from commercial household power supply (e.g. at 100 volts). Lying in the large space between the porous band and the fan, the heater has been incapable of heating the airstream to a required temperature range if its flow rate is high. Thus the flow rate of air has had to be reduced during heating.